The present invention comprises a new and distinct cultivar of hydrangea, botanically known as Hydrangea macrophylla, and hereinafter referred to by the cultivar name ‘Hopcorn’. The new cultivar originated from a naturally occurring branch mutation of the parent hydrangea cultivar ‘Mathilde Gutges’ (unpatented) found in 1998 in Huissen, The Netherlands. The flowers of the mutant plant had smaller sepals and each sepal was cupped, unlike the normal flat sepals of the mutation parent plant.
Like the mutation parent, ‘Hopcorn’ has pink flowers which can turn blue when an aluminum treatment has been applied in combination with growing the plant in acid soil. Hydrangea cultivar ‘Hopcorn’ has been asexually reproduced repeatedly by vegetative cuttings in Huissen, The Netherlands over a five-year period. ‘Hopcorn’ has been found to retain its distinctive characteristics through successive asexual propagations.